Acetaminophen (APAP) is the most common pharmaceutical product associated with drug toxicity. In severe cases, APAP overdose may lead to acute liver failure (ALF) and death. Over 100,000 telephone calls concerning APAP overdose are made to poison control centers in the U.S. annually. The FDA estimates that approximately 450 deaths are related to APAP overdose annually. For patients that seek treatment within 24 hours of an APAP overdose, and are able to provide accurate information regarding the time and amount of APAP ingested, APAP overdose is relatively straightforward to diagnose and treat. However, current methods of diagnosing APAP overdose, such as the Rumack nomogram, are not very useful to diagnose patients after 24 hours of an APAP overdose, when information regarding time and dose of APAP ingested is not available, or patients that use alcohol, chronically ingest supratherapeutic doses of APAP, or use sustained release APAP formulations. Other laboratory tests, such as serum alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST), indicate the occurrence of liver damage, but neither bioindicator is specific to APAP overdose.
Accordingly, a need exists in the art for a method of accurately diagnosing APAP toxicity, including occult APAP poisoning, even 24 hours or longer after the overdose.